Hypogenic Karst and Its Implications for Minnesota Hydrogeology

Recent advances in karst research have provided a better understanding of hypogenic speleogenesis—i.e., the formation of caves and other solution-enlarged permeability structures by upwelling waters—and how it integrates with hydrogeologic processes. Southeastern Minnesota has several carbonate units containing features that are being reinterpreted as examples of hypogenic karst processes. Examples of hypogenic features and karst systems can be found in units such as the Dubuque Formation and the Prairie du Chien Group. The latter is also associated with several examples of breccia pipes in the overlying St. Peter Sandstone, including one in an actively developing area of the Minneapolis-St. Paul metropolitan area.